Separate lettuce leaves into cups. Slight browning on the outer leaves is normal and edible, but you may trim outer leaves if desired. Stem and coarsely chop cilantro. Trim cucumbers and, using a peeler, shave into long ribbons, stopping when you reach seeds. Stack ribbons and cut into long matchsticks. Trim radishes, halve, and slice into thin half-moons. Mince four radish half-moons and eight matchstick carrots to garnish sauce. Zest one lime, then halve and juice both limes.

Place a large pan with 2 tsp. olive oil over high heat. Add ground pork, banh mi seasoning, 1/2 tsp. salt, and 1/4 tsp. pepper to very hot pan and cook 8-10 minutes. Break meat up with a spoon until no pink remains and meat is slightly caramelized.

Combine 3 Tbsp. lime juice, 1/3 the Sriracha (to taste), sugar, 1 tsp. lime zest, minced radish, minced carrot, 1/4 tsp. salt, half the cilantro, and 1/3 cup water in a small bowl. Add half the fish sauce, taste, and add more if desired for added fermented flavor. Sauce should be thin, sweet, sour, and slightly spicy. Add additional water 1 Tbsp. at a time to mellow flavors, if desired.

Place a lettuce cup on work surface (or layer two leaves for extra crunch and structural support). Fill with a few spoonfuls of pork mixture and top with half-moon radishes, matchstick carrots, and cucumbers. Repeat for each lettuce cup.

Arrange assembled lettuce wraps on a plate. Serve sauce on side and use to taste on lettuce cups. Garnish with remaining cilantro and Sriracha (to taste), if desired.